Gaseous fuel engines are known for their ability to burn clean relative to their compression ignition engine counterparts. However, gaseous fuels are well known for the difficulty in attaining successful ignition. Some gaseous fuel engines utilize a spark plug, whereas other engines are known for utilizing a small amount of distillate diesel fuel that is compression ignited to in turn ignite a larger charge of gaseous fuel. Practical spatial limitations in and around an engine often make it difficult to find space for all of the plumbing and hardware associated with supplying two different fuels to each combustion chamber. U.S. Pat. No. 7,373,931 teaches a dual fuel engine that utilizes a small quantity and compression ignited distillate diesel fuel to ignite a larger charge of gaseous fuel. This reference teaches the use of a fuel injector with nested needle valve members to facilitate injection of both the gaseous and liquid fuels from the same injector into each engine cylinder. However, the structure of the injector can lead to cross leakage between fuels, leakage of fuel into the engine cylinder and stacked tolerances that may lead to substantial performance variations when the fuel injectors are mass produced. In addition, the injector structure inherently requires different injection patterns depending upon whether the fuels are being injected individually or at the same time.
Apart from the potential problems noted above, there may also be issues with regard to packaging a dual fuel injector with two electrical actuators and control valves in the limited space available in a cylinder head mounting of an engine. The '931 patent shows side-by-side electronically controlled valves for separately controlling gaseous fuel and liquid fuel injection events. In some instances, there may not be enough available space to provide for a side-by-side mounting as shown in this reference.
The present disclosure is directed toward one or more of the problems set forth above.